eloquent javascript modern introduction to programming

The Promise programming model is also known as thenable, which can be understood as deferred execution. Each Promise has a unique interface called then, which is invoked when Promise fails or succeeds. It represents a result of an operation that may run for a long time and does not necessarily have to be completed. Instead of blocking and waiting for a long operation to complete, this pattern returns an object that represents the result of a commitmen

best to add var _ this = this; in the first line of the class definition, so that in this. the bound pointer can also be easily used in xxx = function.2. InheritanceThere are two main methods to implement inheritance: the first is to use the prototype of javascript itself to implement inheritance by assigning values to prototype and changing its constructor attribute; the second method is to manually copy all attribute methods of the parent object to

1. I am a year earlier than JSThe 2.web browser is one of the hosting environments implemented by the ECMAScript.Other hosting environments that implement ECMAScript include node and Adobe Flash3.ECMAScript Main Provisions JS components: syntax, keywords and reserved words;variables, data types, operators, statements, types, objects;4.dom maps the entire page into a multi-node structure. Dom independent of PlatformJavaScript Advanced Programming (3rd